The Hypothalamus and the Pituitary

Question 1

Which glands coordinate the majority of the glands in the endocrine system?

Answer 1

Pituitary and Hypothalamus

Question 2

Where does the pituitary gland sit in relation to the hypothalamus?

Answer 2

Immediately below

Question 3

What is the function of the hypothalamus?

Answer 3

Neuroendocrine function- releases chemicals into blood to act at distal sites

Question 4

In which bone in there a depression in which the anterior pituitary sits?

Answer 4

Sphenoid bone

Question 5

Which part of the pituitary is an extension of the hypothalamus?

Answer 5

Posterior pituitary- extension of neural tissue

->anterior pituitary gland is a true endocrine gland but is still linked to hypothalamus

Question 6

What is the name given to the stalk which connects the hypothalamus to the pituitary?

Answer 6

Infundibulum

Question 7

What provides the connection between the anterior pituitary and the hypothalamus?

Answer 7

Capillary portal system

Question 8

Which part of the pituitary gland is a true endocrine gland?

Answer 8

Anterior pituitary gland

Question 9

Which part of the pituitary makes up the majority of it?

Answer 9

Anterior- 2/3
Posterior- 1/3

Question 10

The posterior pituitary is neuroendocrine. What role does it have?

Answer 10

Consists of axons and nerve terminals of hypothalamic neurons and secretes neurohormones which are made in the hypothalamus

Question 11

List some of the stimuli which create an input to the hypothalamus in which the hypothalamus then responds to.

Answer 11

Cold
Stress
Puberty
Sleep
Pregnancy
Metabolic demand

Question 12

What is the goal of the hypothalamus?

Answer 12

To maintain homeostasis

Question 13

After the hypothalamus receives input from stimuli, how is a response generated to maintain homeostasis?

Answer 13

Via the pituitary gland

Question 14

Both the hypothalamus and the anterior pituitary release tropic and non-tropic hormones.
What is meant by a tropic hormone?

Answer 14

A hormone which alters the release of another hormone

Question 15

Which type of hormones are all hormones released from the hypothalamus?

Answer 15

Neurohormones

Question 16

Which type of hormones are all hormones released from the posterior pituitary?

Answer 16

Neurohormones

Question 17

Which type of hormones are all hormones released from the anterior pituitary?

Answer 17

Classic endocrine hormones

Question 18

Name the two forms of hypothalamic neurohormones.

Answer 18

Tropic
Non-tropic

Question 19

Where are non-tropic hormones produced and where do they travel to?

Answer 19

Non tropic hormones are produced in the hypothalamus and travel to the posterior pituitary.
They are then released into the blood

Question 20

Where are all the tropic hormones secreted?

Answer 20

Into capillaries leading into the anterior the anterior pituitary.

Question 21

Therefore:
a. which type of hormone are all the hormones of posterior pituitary gland?
b. which type of hormone are all the hormones of anterior pituitary gland?

Answer 21

a. Posterior= non-tropic
b. Anterior= tropic

Question 22

Where are the non-tropic hormones of the posterior pituitary derived from?

Answer 22

Magnocellular neurons

Question 23

Where do the magnocellular neurons have their cell bodies?

Answer 23

Hypothalamus

Question 24

The posterior pituitary releases two non-tropic neuroendocrine hormones.
Name them.

Answer 24

Vasopressin
Oxytocin

Question 25

What role does vasopressin have?

Answer 25

Maintains water balance

Question 26

What role does oxytocin have?

Answer 26

Stimulates uterine contraction at parturition (giving birth) Aids expression of milk in lactating breast

Question 27

What can vasopressin also be known as?

Answer 27

ADH- anti-diuretic hormone

Question 28

Name the five types of hypothalamic 'releasing hormones' which are tropic hormones.

Answer 28

TRH- thyrotropin releasing hormone CRH- corticotropin releasing hormone GHRH- growth hormone releasing hormone GnRH- gonadotropin releasing hormone PRH- prolactin releasing hormone

Question 29

Name the two types of hypothalamic 'inhibiting hormones' which are tropic hormones.

Answer 29

GHIH- growth hormone inhibiting hormone PIH- prolactin inhibiting hormone

Question 30

What is GHIH also known as?

Answer 30

Somatostatin

Question 31

What is PIH also known as?

Answer 31

Dopamine

Question 32

Dopamine most commonly acts as a neurotransmitter but what is it's endocrine role?

Answer 32

Inhibits the release of prolactin from the anterior pituitary gland

Question 33

All tropic hormones are peptide hormones except dopamine. Which type of hormone is dopamine?

Answer 33

Amine hormone

Question 34

What is the hypothalamo-hypophyseal portal system?

Answer 34

Network of tiny vessels which transfer tropic hormones from the hypothalamus to the anterior pituitary

Question 35

Name the five tropic hormones released from the anterior pituitary gland.

Answer 35

TSH- thyroid stimulating hormone ACTH- adrenocorticotropic hormone FSH- follicle stimulating hormone LH- luteinising hormone GH- growth hormone

Question 36

RECAP- what do tropic hormones do?

Answer 36

Control the secretion of other hormones

Question 37

Prolactin is another hormone produced by the anterior pituitary gland and is the only hormone produced here that is not a tropic hormone. What does prolactin do?

Answer 37

Directly stimulates milk production from the breast during lactation

Question 38

In terms of anterior pituitary feedback control, there are three integration centres. List them.

Answer 38

1. Hypothalamus 2. Anterior pituitary 3. Target endocrine cell e.g. thyroid gland, adrenal cortex etc.

Question 39

Hormones themselves act as negative feedback signals- each hormones feeds back to inhibit hormone secretion by integration centres earlier in the reflex. What is meant by long-loop feedback?

Answer 39

Feedback from the endocrine target (last integration centre in the loop hence long loop)

Question 40

Hormones themselves act as negative feedback signals- each hormones feeds back to inhibit hormone secretion by integration centres earlier in the reflex. What is meant by short-loop feedback?

Answer 40

Feedback from the anterior pituitary to the hypothalamus

Question 41

Endocrine disorders can be described as hyposecretion. What does this mean?

Answer 41

Too little hormone secreted.

Question 42

Endocrine disorders can be described as hypersecretion. What does this mean?

Answer 42

Too much hormone secreted

Question 43

Hypo or hypersecretion can be as a result of primary, secondary and tertiary endocrine disorders. What happens in primary endocrine disorders?

Answer 43

There is a defect in the cells that secrete the hormone

Question 44

Hypo or hypersecretion can be as a result of primary, secondary and tertiary endocrine disorders. What happens in secondary endocrine disorders?

Answer 44

Too much or too little tropic hormone is released from the pituitary

Question 45

Hypo or hypersecretion can be as a result of primary, secondary and tertiary endocrine disorders. What happens in tertiary endocrine disorders?

Answer 45

There are hypothalamic defects releasing too much or too little hormone from the hypothalamus

Question 46

What can cause hyporesponsiveness?

Answer 46

-Alterations in receptors for hormones -Disordered post-receptor events -Failure of metabolic activation or hormone -Antagonistic effects

Question 47

What can cause hyperresponsiveness?

Answer 47

Permissive effects- when one hormone enhances the activity of another hormone

Question 48

What happens if there is prolonged exposure to low hormone concentration?

Answer 48

Up-regulation of receptor for that hormone ->this is so any hormone in plasma is more likely to bump into a receptor

Question 49

What happens if there is prolonged exposure to high hormone concentration?

Answer 49

Down-regulation of receptor for that hormone

Question 50

What is meant by antagonistic effects?

Answer 50

Presence of one hormone reduces the effect of another

Question 51

Give an example of permissive effects.

Answer 51

Epinephrine causes modest lipolysis but when thyroid hormones are also present, greatly increases lipolysis

Question 52

Give an example of antagonistic effects.

Answer 52

Growth hormone impairs glucose uptake